Efforts have been made to automatize routines in an automobile manufacturing process with manipulators. For example, various processes such as welding processes, coating processes, and other processes have been automatized by a teaching playback process which reproduces actions that have been taught in advance.
If not only simple teaching playback processes, but also different actions depending on workpieces, are made possible, then the manipulators become applicable to a wider range of applications. For example, it is preferable for a manipulator to be able to grip workpieces of different shapes or workpieces disposed in different directions.
For gripping workpieces of different shapes with a manipulator, Japanese Laid-Open Patent Publication No. 2006-026875 discloses a means for calculating a condition for maximizing points of contact with a workpiece as an optimum gripping condition.